alter table谁知道Access里Alter Table语句是什么格式？?

alter table 时间:2022-03-01 阅读:()

在alter table 语句中定义视图的语法规则是什么

alter table 是修改表，ALTER VIEW 才是修改试图，下面是语法规则： ALTER VIEW 更改一个先前创建的视图（用 CREATE VIEW 创建），包括索引视图，但不影响相关的存储过程或触发器，也不更改权限。有关 ALTER VIEW 语句中所用参数的更多信息，请参见 CREATE VIEW。语法 ALTER VIEW [ < database_name > .] [ < owner > .] view_name [ ( column [ ,...n ] ) ] [ WITH < view_attribute > [ ,...n ] ] AS select_statement [ WITH CHECK OPTION ] < view_attribute > ::= { ENCRYPTION | SCHEMABINDING | VIEW_METADATA } ALTER TABLE 通过更改、添加、除去列和约束，或者通过启用或禁用约束和触发器来更改表的定义。语法 ALTER TABLE table { [ ALTER COLUMN column_name { new_data_type [ ( precision [ , scale ] ) ] [ COLLATE < collation_name > ] [ NULL | NOT NULL ] | {ADD | DROP } ROWGUIDCOL } ] | ADD { [ < column_definition > ] | column_name puted_column_expression } [ ,...n ] | [ WITH CHECK | WITH NOCHECK ] ADD { < table_constraint > } [ ,...n ] | DROP { [ CONSTRAINT ] constraint_name | COLUMN column } [ ,...n ] | { CHECK | NOCHECK } CONSTRAINT { ALL | constraint_name [ ,...n ] } | { ENABLE | DISABLE } TRIGGER { ALL | trigger_name [ ,...n ] } } < column_definition > ::= { column_name data_type } [ [ DEFAULT constant_expression ] [ WITH VALUES ] | [ IDENTITY [ ( seed , increment ) [ NOT FOR REPLICATION ] ] ] ] [ ROWGUIDCOL ] [ COLLATE < collation_name > ] [ < column_constraint > ] [ ...n ] < column_constraint > ::= [ CONSTRAINT constraint_name ] { [ NULL | NOT NULL ] | [ { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] [ WITH FILLFACTOR = fillfactor ] [ ON { filegroup | DEFAULT } ] ] | [ [ FOREIGN KEY ] REFERENCES ref_table [ ( ref_column ) ] [ ON DELETE { CASCADE | NO ACTION } ] [ ON UPDATE { CASCADE | NO ACTION } ] [ NOT FOR REPLICATION ] ] | CHECK [ NOT FOR REPLICATION ] ( logical_expression ) } < table_constraint > ::= [ CONSTRAINT constraint_name ] { [ { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] { ( column [ ,...n ] ) } [ WITH FILLFACTOR = fillfactor ] [ ON { filegroup | DEFAULT } ] ] | FOREIGN KEY [ ( column [ ,...n ] ) ] REFERENCES ref_table [ ( ref_column [ ,...n ] ) ] [ ON DELETE { CASCADE | NO ACTION } ] [ ON UPDATE { CASCADE | NO ACTION } ] [ NOT FOR REPLICATION ] | DEFAULT constant_expression [ FOR column ] [ WITH VALUES ] | CHECK [ NOT FOR REPLICATION ] ( search_conditions ) }

在SQL中，怎样用一个Alter Table命令修改某列的计算公式？

查询了一下 SQL Server 2008 的语法手册百关于 ALTER TABLE 的参数。 ALTER COLUMN 指定要更改命名列。如果兼容级别等于或低于 65，则不允许使用 ALTER COLUMN。有关详细信息，请参度阅sp_dbcmptlevel (Transact-SQL)。修改后的列不内能容为下列任何一种列：数据类型为 timestamp 的列。表的 ROWGUIDCOL 列。计算列或用于计算列的列。文档显示：修改后的列不能为计算列或用于计算列的列。